Highly sensitive detection for xanthine by combining single-band red up-conversion nanoparticles and cycle signal amplification strategy based on internal filtration effect.

A novel colorimetric and fluorescence dual-mode sensing system based on UCNPs for the detection of XA is proposed by combining the IFE and the cyclic signal amplification strategy. The proposed assay was applied to the determination of XA in serum samples and the recovery rates of the spiked samples were in the range of 96.3–104.3%, indicating the proposed assay could be adapted for rapid sensitive detection of XA in real samples. [Display omitted] • A highly sensitive dual-mode sensor platform for detecting XA was constructed. • The high sensitivity and selectivity could be achieved by cycle signal amplification strategy. • The fluorescent and colorimetric dual readout signal make the analysis results convincing. • The linear detection range of XA was 2.5–150 μM with LOD of 0.58 μM. Up-conversion nanoparticles (UCNPs), especially single-band bright red UCNPs, have better penetration of biological tissues, absorb less lost energy, and have higher sensitivity and accuracy in the determination of actual biological samples in the field of biosensing. Here, a novel colorimetric and fluorescent dual-channel method based upon an internal filtration effect (IFE) quenching mechanism was proposed for the quantitative analysis of xanthine (XA) by using red UCNPs as fluorescence indicator and 3,3′,5,5′ -tetramethylbenzidine (TMB) as chromogenic substrate. The sensitivity of the detection system was also enhanced by a cycle signal amplification strategy based on the Fenton reaction. Under the best conditions, the detection limits of XA by fluorescent and colorimetric methods were 0.58 μM and 1.19 μM, respectively. The developed method was applied to the detection of XA in actual serum samples, and the recoveries of the spiked samples by fluorescent and colorimetric methods were in the range of 96.3–104.3 % and 94.3–105.4 %, respectively. In addition, the commercial ELISA method was used to verify the application of the proposed method and the test results of XA were close to those obtained by fluorescent and colorimetric methods, indicating that the accuracy of the developed nanosensing system was acceptable. [ABSTRACT FROM AUTHOR]